Microbial degradation of arabian light crude oil by Acinetobacter sp. A54 = Acinetobacter sp. A54에 의한 arabian light 원유의 분해

Abstract

Bacterial strains which degrade Arabian Light crude oil were isolated by enrichment culture from oil-spilled soil. The strain A54 was finally selected after testing emulsifying activity and oil conversion rate. Strain A54 was identified as a Acinetobacter sp. based on the morphological, biochemical and physiological characteristics. It appears to be highly specialized for growth on Arabian Light crude oil in minimal salts medium since it showed preference for oil or degradation products as substrates for growth. It was found that it could grow on at least fifteen different hydrocarbons. The optimum cultural and environmental conditions were as follows; 25°C for temperature, 7.5 for pH, 2.0% for NaCl concentration and 2.0% for crude oil concentration. Additionally, the optimal concentration of NH4NO3 and K2HPO4 were 12.5 mM and 0.057 mM, respectively. Cell growth and emulsifying activity as a function of time were also determined. Crude oil degradation and the reduction of product peaks were identified by the analysis of remnant oil by gas chromatography. Approximately 63% of crude oil were converted into a form no longer extractable by mixed organic solvents.